Improvement in fire-proof floors



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GEORGE H; JOHNSON .AND WILLIAM FREEBORN, OF CHICAGO, ILLINOIS.

IMPROVEMENT IN FIRE-PROOF FLOORS.

Speciication forming part of Letters Patent No. 132,292, dated October15, 1872.

To all 'whom it may concern:

Be it known that I, GEO. H. JOHNSON and WM. FREEBORN, of Chicago, in thecounty of Cook and State of Illinois, have invented an ImprovedConstruction of Fire-Proof Floors, of which the following is aspecification:

Our invention is an improvement on the construction of hollowtilefloors, invented by George H. `Johnson and B. Kreischer, patented March21, 1871, No. 112,926 and No. 112,930.

The aim of the architect, in the construction of ,fire-proof as well asother buildings,

4particularly those of the larger and more imposing kind, is chieiiy tosecure the maximum of strength, durability, and compactness consistentwith the greatest economy of labor and material.

In previous inventions in the line of hollowtile floors we have securedthis result but imperfectly or in part, since it has been demonstrated.by practical test that the desired measure of economy of space,material, and labor was largely wantin g. In the present instancewe havedevised a floor or ceiling which occupies much less space verticallythan the width of ordinary small-sized flanged iron beams or girders,and is composed of separate tiles aggregating a less mass and weightthan a brick or stone arch of equal width, while capable of supportingan equal or greater strain, presenting a smooth er surface, andrendering grouting unnecessary, besides possessing greater re or heatresisting qualities.

Referring to the accompanying drawing, Fig. 1 is anisometrical view of asection of a floor and ceiling, constructed after our plan,

and supported by iron beams; Fig. 2 is a siniilar View, woodentruss-beams being substituted for the iron and Fig. 3 is a longitudinalsection thereof.

We construct the iioor of tubes or hollow tiles, which are of equalvertical thickness and Y preferably arranged so as to break joints.77

These tubes are of irregular form, but present in every case four sharpedges or corners. The central tube a is the key, and the two outer tubesc c are grooved or rabbeted to form a shoulder which rests on the lowerflange of the beam or girder F. Between the key a and each of these (c)we insert tubes b, which are of a rhombic form in cross-section. The

lnumber of these tubes b b will in every case correspond to the'distance between the beams or girders. Any one of them may besubstituted for any other, being all made in the same die or mold. Thusthe only tube or tile composing the floor, which will in any case needchange of form, is the key a, and that only in respect to width toaccommodate any possible variations of space between the beams F, whereit happens that the other parts, b b c c, do not fill the space witheXactness. To provide for this contingency, in practice-keys a ofvarious thicknesses will be manufactured and furnished in suitablenumber with the tubes b b and c c.

This construction and arrangement of tiles provides a flat surface onboth sides of the ceiling or floor, and admits of the woodenflooring-strips B C being laid thereon without the aid of grouting orfilling, as is the case when the old form of arch is used. The end ofthe joists O fit under the upper flange of the girders F, and thus thewhole of the iiooring, including the boards D, is also held down withoutthe necessity of nails or spikes, or other means of securing it. Thisstatement does not so well apply to the construction shown in. Fig. 2,where wooden truss-beams G are employed, the same resting on iron platesI, which form the shoulder-supports of the tubes c c.

It will be observed that, when desired or necessary, particularly in theclass of smaller buildings, the wooden ooring B O D may be dispensedwith, and a smaller-sized girder employed,-so that the upper and undersurface of the tiles will constitute the licor and ceiling,respectively, of two apartments, one above the other. In any event, nolathing of any kind will be required, a thin coat of hard finish beingalone applied to the under surface of the tubes.

Having thus described our invention, what we claim as new, and desire tosecure by Letters Patent is- 1. The combination, with flanged girders,of

the grooved or shouldered outer tubes c c, ke5T and arranged to form efiat upper and under a, and the intermediate tubes b b, all of thesurface of the strips B and joists G, as shown form shown, and arrangedas herein described, and described, for the purpose specied.

whereby they form a, fiat surface on the upper GEO. H. JOHNSON. andunder side, and are adapted to ll differ- WM. FREEBORN. ent spacesbetween the girders, as specied. Witnesses:

2. The combination, with the double-flanged EDWIN ROBT. HALL,

girders F, of the tubes a b b o o, constructed WM. B. KERFOOT.

